This invention relates to improved walnut shell flour based powder compositions having good adsorption of body fluids. More particularly, it relates to walnut shell flour based face powder compositions.
Cosmetic powders having oil absorption properties have conventionally used a major proportion of talc. Talc, however, has certain disadvantages. For instance, when wetted with water and dried it forms hard agglomerates which are irritating to the skin. This property is reduced by replacing some of the talc with cornstarch, but cornstarch is an excellent medium for bacterial growth and is thereby another source of irritation.
White et al (U.S. Pat. No. 3,278,383) disclose topical therapeutic powder compositions containing a major proportion of finely divided alpha cellulose. The powders are alleged to be non-staining, highly absorbent, soft and smooth, free of starch and boric acid and completely non-caking and non-crusting. The White et al compositions contain bacteriostatic and fungistatic agents and are primarily baby powders.
While corn cob dust or corn cob flour or finely divided alpha cellulose have the essential properties required, they have a tendency to rot, causing them to change to a gray powder which is not readily colored to achieve an acceptable skin tone. Moreover, corn cob dust or corn cob flour is becoming increasingly less available since it is being used in the manufacture of furfural; it is also being used in the grain alcohol industry and as a carrier for pesticides.
Walnut shell flour on the other hand is readily available, has properties very similar to corn cob dust or corn cob flour and, in addition, has a more consistent color and can be converted readily, by the addition of small amounts of coloring materials, such as iron oxides (red, yellow and brown), ultramarine blue, etc., to a universal skin tone or the like. This has considerable advantage in facial powders.
Walnut shell flour is obtained in fine particle size (&lt;40.mu.) and is more transparent than talc or kaolin. However, it is readily used in combination therewith to provide face powders with a high degree of transparency and oil absorbency. In addition, walnut shell flour is more readily compacted than corn cob dust or corn cob flour. This is a desirable factor in the preparation of compacted or pressed face powders.
Particle size is important in face powder preparations since the walnut shell flour becomes less transparent, rougher, more dusty, loses absorption and becomes less compactible as the particle size increases. Thus, the compositions of the present invention preferable utilize finely divided walnut shell flour, i.e. having a particle size less than about 30 microns.
The face powder compositions of the present invention may contain in addition to walnut shell flour other fillers, such as talc, kaolin, tatanium coated mica, and the like, to provide additional absorption of body oils and moisture. Total filler content of the powders ranges from about 90% to 99%, while the walnut shell flour content will vary from about 30% to 99%, and preferably from about 30% to 60% for loose powders and 40% to 80% for pressed powders.
The compositions may also contain metallic stearates, such as zinc or magnesium stearates, to assist in skin adhesion, and as a binder. In addition, they provide a smooth, supple feel.
Medicaments, e.g., fungicides, such as Vancide 89RE, N-(trichloromethylmercapto)-4-cyclohexane 1,2-dicarboximide; binders, such as triethyl citrate, mineral oil or polyethylene glycol stearates; colorants, such as red, yellow, and brown oxides; fragrances, and the like, may also be included in the composition.